1. Technical Field
The embodiments herein generally relate to the field of multi layered nanofibrous wound dressings and more particularly to an electro spun multi layered nanofibrous and polymeric wound dressing loaded with an herbal extract. The embodiments herein also relate to a method of synthesizing the electro spun polymeric wound dressing.
2. Description of the Related Art
The Melilotus officinalis extract is a major ingredient of a modified herbal based compound Semelil (ANGIPARS™), which is a promising candidate drug for wound healing. The results of the recent clinical trials showed that the new herbal extract, ANGIPARS™, is very effective for treatment of foot ulcers and authors suggest that this novel drug can be superior to other treatments and can be used in all types of ulcers. Experimental studies have shown no chronic or acute toxicity for ANGIPARS™.
The commercial product, ANGIPARS™, provides Melilotus officinalis extract in an oral form (capsule) and a topical form (3% cream) for the treatment of wounds. The major disadvantages with the oral and the topical forms are their administration for two or three times a day, need for exchanging a wound bandage after each administration and no/lack of dose control in each administration. This limits the application of Melilotus officinalis extract as a cream i.e. topical form for treatment of wounds.
On the other hand, the electro spun nanofibers have many characteristics that make them ideal candidates for wound healing applications. The electro spun nanofibers meet many characteristics of an ideal wound dressing. These include: efficiency as bacterial barrier, absorption of excess exudates or wound fluid, provision and maintenance of a moist environment or appropriate water vapor transmission rate, provision of adequate gaseous exchange, ability to conform to the contour of the wound area, functional adhesion, i.e., adherence to healthy tissue but non-adherence to wound tissue and painless to patient and ease of removal. The high surface area to volume ratio of the electro spun nanofibers facilitates oxygen permeability and allows fluid accumulation, which are highly desirable in the wound healing course. The pores in non-woven form of electro spun scaffolds (normally 1-10 μm) are small enough to prevent a bacterial penetration. Meanwhile the nanoscale fibers that impart the dressing with small interstices and high effective surface area can promote homeostasis. Such a function of homeostasis is activated from the physical feature of the nanofibrous dressings without using a haemostatic agent.
Further a therapeutic agent can be incorporated into the electro spun nanofibers to give them additional benefits for wound dressing applications. Antibiotics, growth factors and anesthetic are some therapeutic agents incorporated in the electro spun nanofibers used as wound dressing. Meanwhile a controlled release of therapeutics from the electro spun nanofibers is another benefit of the electro spun nanofibers as wound dressing.
WIPO patent application no. 2010/103324 A2 discloses an electro spun wound dressing comprising a biodegradable polymer or co-polymer and a nonsteroidal anti-inflammatory drug.
WIPO patent application no. 2008/010199 A2 discloses a mesh comprising nanofibers of oxidized polysaccharide and a fiber forming polymer.
WIPO patent application no. 2011/008842 A2 explains a preparation of electro spun silk fibroin/polyethylene oxide blend nanofibers as potential material for biomedical application such as wound dressing. The electro spun silk fibroin/PEO mates demonstrated suitable physical and bio-functional properties.
US patent application no. 2007/0155273 A1 discloses an electro spun biodegradable poly (ester-amid) fabric for biomedical application such as scaffold for tissue engineering and wound healing treatment. It also disclosed an incorporation of drug or other agent in poly (ester-amid) nanofibers to accelerate a healing.
Considering the benefits of the electro spun nanofibers as wound dressing and limitations of Melilotus officinalis extract cream, the incorporation of Melilotus officinalis extract within the electro spun nanofibers can lead to a development of an efficient device for wound healing application.
On the other hand, a wide range of natural and synthetic polymers can be electro spun into nanofibers matrices with structural integrity and specific fiber arrangements. Polymers used in electro spun membranes as wound dressing include collagen, gelatin, fibrinogen, chitosan, PU, PCL, PLA, and PLGA, or some blends of them.
Chitosan (CS), a biopolymer comprising glucosamine and N-acetyl glucosamine, is an N-deacetylated product of chitin and one of the most abundant polysaccharides in nature. Chitosan has many advantages such as biocompatibility, biodegradability, haemostatic activity, anti-infection and wound healing acceleration properties when used in a wound dressing application For these reasons, chitosan has been one of the important biomaterials for a wound management in the recent years. An electro spinning of chitosan to a fibrous structure is difficult because it has a poly cationic character in an acidic aqueous solution due to the many amino groups in its backbone. Its poly cationic nature excessively increases the surface tension of the solution. Nevertheless, the fibrous structures were successfully formed by the electro spinning chitosan solutions in 90 wt % aqueous acetic acid solutions or by using an environmentally harmful and toxic solvent like trifluoro acetic acid (TFA) or TFA/dichloromethane (DCM). Since the electro spinning of chitosan itself proved to be difficult, chitosan was mixed with other synthetic or natural polymers, such as PEO, PVA, poly(lactic acid) (PLA) or its copolymers, silk fibroin (SF), and collagen. The resultant chitosan fibers need to be cross-linked to maintain their structural integrity, as they can readily swell in an aqueous solution. Glutaraldehyde (GA) is commonly used for cross-linking chitosan nanofibers. However GA is a toxic reagent and hence is not proper/advised for use in biological systems.
A water-soluble bi-functional natural cross linking reagent, genipin, has been used for cross linking the chitosan in the form of a film or particles. The resulting cross-linked complexes are not cytotoxic for the animal and human cells examined so far. The safety and the beneficial actions of the genipin emerge from a number of research projects for the therapies in the areas of diabetes, periodontitis, cataract, hepatic dysfunction, as well as in wound repair and nerve regeneration. But none of the prior arts provides an electro spun nanofibers incorporated with an herbal extract and cross-linked using genipin.
The Melilotus officinalis extract in a topical form is not provided. The Melilotus officinalis extract in a topical form obviates cream limitation and also provides additional benefits for wound healing purposes. Also, a cross-linking of chitosan nanofibers with a low toxic reagent is required.
Hence there is a need to provide a wound dressing containing an herbal extract with cross linked nanofibers to provide a controlled release of the herbal extract in a wound.
The above mentioned shortcomings, disadvantages and problems are addressed herein and which will be understood by reading and studying the following specification.